A wide variety of wet wipes dispensing containers are available in the market today. These containers may be broadly categorized into two classes: reach-in and pop-up. Within the pop-up category, some containers provide a stack of flat wipes, which are interfolded, which are most commonly dispensed from a tub. Other containers provide a roll of wipes, perforated at their edges, which are dispensed from an upright cylindrical container. The pop-up style containers have gained popularity because the wet wipe is more readily available to the user. Although there is a greater opportunity for the wipes in a pop-up style container to at least partially dry out, improvements in container design have mitigated this problem.
However, for pop-up style containing a stack of wipes there are occasions where the pop-up feature fails and the user needs to reach into the container to retrieve the next wipe. These failures are most often caused by missed interfolds. Unfortunately, current pop-up containers do not have openings that enable the user to reach into the container, while at the same time maintaining a sufficiently good seal to prevent substantial dry-out of the wipe s within the container.
It has now been discovered that certain pop-up style wet wipe containers can provide simultaneous pop-up and reach-in capability. This is not only useful for retrieving wipes that failed to dispense, but it also enables users to push the popped-up wipe back into the container to improve moisture retention or to more readily maintain sanitary conditions, and thereafter easily retrieve the wipe.
Hence in one aspect, the invention resides in a wet wipe container containing interfolded or perforated wet wipes and having a pop-up style dispensing means positioned beneath a retractable lid, said dispensing means comprising a rigid port surrounding a flexible, rubber-like material or sheet having one or more slits through which individual wet wipes are removed from the container when the lid is open, wherein the flexibility of the sheet and the length of the slit(s), in combination, are sufficient to enable a user to reach into the container and easily retrieve a wet wipe in the event the pop-up feature fails.
In another aspect, the invention resides in a wet wipe container containing interfolded or perforated wet wipes and having a pop-up style dispensing means positioned beneath a retractable lid, said dispensing means comprising a rigid port surrounding a flexible, rubber-like material or sheet having one or more slits through which individual wet wipes are removed from the container when the lid is open, wherein the dispensing means has a Penetration Index of from about 50 to about 600 grams.
For purposes herein, the xe2x80x9ccontainerxe2x80x9d can be any container suitable for storing and dispensing wet wipes including, but not limited to, tubs, canisters, soft packs, and the like.
The configuration and the length of the slit(s) in the flexible, rubber-like material or sheet can vary giving consideration to a number of factors, including evaporation losses, ease of wipe removal, sufficient frictional engagement to maintain the pop-up feature and access to the wipes within the container in the event the pop-up feature fails. It has been found that multiple intersecting slits works well to meet all of the foregoing considerations. This will be described in more detail with reference to the Drawings.
The nature of the flexible, rubber-like material or sheet having the slits must be sufficiently stiff to maintain a reasonable impediment to evaporation losses and to hold the wet wipes in the pop-up position. At the same time, it must be pliable enough and elastic in order to enable the user to reach into the container with the fingers sufficiently far, without hurting his/her fingers, to grasp a wipe from the top of the stack, even when the stack is down to one remaining wipe. To meet these requirements, the properties of the flexible, rubber-like sheet combine with the selected slit configuration to attain the desired end result. It will be appreciated that as the length of the slits increases, it becomes easier to reach one""s finger into the container because the opening is larger. The same is true as the stiffness decreases. Although the rubber-like material can take many forms, a sheet form is suitable because it is readily made for commercial purposes.
In an effort to quantify the properties of the rubber-like material or sheet, the relevant properties can be described in terms of the hardness, stiffness, thickness, elasticity and any combination thereof.
More specifically, the Shore A hardness (as measured by ASTM D2240) of the flexible, rubber-like sheet or material can be about 100 or less, more specifically from about 20 to about 70, and still more specifically from about 30 to about 60.
The Gurley stiffness of the flexible, rubber-like sheet or material (as measured by ASTM D 6125-97 xe2x80x9cStandard Test Method for Bending Resistance of Paper and Paperboardxe2x80x9d) can be about 10,000 milligrams of force (mgf) or less, more specifically from about 100 to about 8000 mgf, more specifically from about 200 to about 6500 mgf, and still more specifically from about 300 to about 1500 mgf.
The thickness of the flexible, rubber-like sheet can be about 0.1 millimeter or greater, more specifically from about 0.1 to about 2 millimeters, and still more specifically from about 0.8 to about 1.5 millimeters.
The elasticity of the flexible rubber-like material or sheet, as characterized by the tensile stress at 100 percent elongation and measured in accordance with ASTM D412 xe2x80x9cStandard Test Methods for Vulcanized Rubber and Thermoplastic Elastomersxe2x80x9d, can be about 10 megapascals (Mpa) or less, more specifically from about 0.1 to about 7 Mpa, and still more specifically from about 0.5 to about 2.5 Mpa.
Alternatively, the performance of the dispensing means can be measured more directly by using a tensile testing machine to insert a ball-shaped probe into the dispensing opening under controlled conditions and measuring the force required to overcome the resistance of the opening . This simulates the use of one""s finger to reach into the container to retrieve a wipe. In general, the measurement involves placing a container to be tested underneath a specially-designed probe which is mounted to a tensile tester . The tensile tester lowers the probe into the center of the container dispensing means at a predetermined speed and measures the peak load, in grams, required to penetrate the opening. This test, as more specifically described below, results in a value referred to herein as the xe2x80x9cPenetration Indexxe2x80x9d. The containers of this invention can have a Penetration Index of from about 50 to about 600 grams, more specifically from about 100 to about 500 grams, and still more specifically from about 200 to about 400 grams.
The tensile tester is a MTS Sintech 1/G with a MTS 10 pound load cell. The software is Testwrorks for Windows 3.10. The load cell contains a 0.5 inch grip adapter for receiving the metal ball probe. The ball probe used is approximately 4.5 inches long. The bottom portion of the probe, which contacts the sample to be tested, is ball-shaped and has a ball diameter of 0.75 inch. The middle portion of the probe consists of a connecting xe2x80x9cneckxe2x80x9d which is approximately 0.375 inches in diameter and 1.375 inches long. The upper section of the probe is approximately 0.5 inch in diameter and 2.4 inches long. The end of the upper section contains a flat area to allow the probe to fit into the grip adapter of the tensile tester. The flat area is 0.125 inch off of the center of the probe.
When conducting the test, the container to be tested is securely placed on a suitable surface such that the center of the dispensing opening is placed directly underneath the ball probe. The probe is initially positioned such that it is approximately one inch above the dispensing opening. Upon the start of the test, the probe moves downward at a rate of 80 inches per minute for a distance of 2 inches. The probe is held for one second at this bottom position and then is moved upward to its initial position at the same rate. The test is repeated two additional times. The peak load readings from the tensile tester, expressed as grams of force, are averaged and the result is the Penetration Index for the sample.
As used herein, the term xe2x80x9crigidxe2x80x9d is used to mean a level of stiffness commonly associated with materials used to manufacture wet wipes tubs. Numerically, these materials typically have a flexural modulus (as measured in accordance with ASTM D790 xe2x80x9cStandard Test Method for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materialsxe2x80x9d) of about 500 Newtons per square millimeter or greater, more specifically from about 1100 to about 1550 Newtons per square millimeter.
The term xe2x80x9cinterfolded wipesxe2x80x9d, as used herein, means a plurality of wipes, such as in a stack of wipes, in which separate individual wipes are releasably attached to each other by folding an edge of one wipe over the edge of an adjacent wipe.
The term xe2x80x9cperforated wipesxe2x80x9d, as used herein, means a plurality of wipes, such as in a stack or roll, in which individual wipes are defined and interconnected by a series of perforation lines in a continuous sheet, such that each wipe can be detached from the remaining wipes by tearing the sheet along the line of perforations.
Both interfolded wipes and perforated wipes can be used for purposes of this invention.